Discharge valve, booster pump, and hydrogen supply system

Abstract

To reduce a load by shortening a time until an opening state.SOLUTION: A discharge valve comprises: a casing having a housing space part communicated with a fluid discharge hole; a valve seat having an inflow port arranged in the housing space part and communicated with a fluid inflow hole and a discharge port communicated with the fluid discharge hole; a valve body movably supported at a close position and an open position in the housing space part; a valve seat presser member forming an arrangement space inside, and defining a position of the valve seat to the casing; and an energization member for energizing the valve body. The valve seat presser member has a first communication hole for communicating the arrangement space part with the fluid discharge hole, and the first communication hole has a flow passage shape whose resistance against the fluid flowing into the arrangement space part from the fluid discharge hole gets larger than a resistance of the fluid flowing to the fluid discharge hole from the arrangement space part.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a discharge valve, a boost pump, and a hydrogen supply system. [Background technology]

[0002] An example of a conventional discharge valve for a booster pump is described in Patent Document 1 below. The discharge valve described in Patent Document 1 is used in a booster pump for a low-temperature fluid. The discharge valve utilizes a ball and a spring, and opens when a fluid pressure equal to or greater than a predetermined pressure is applied, and closes when the fluid pressure falls below the predetermined pressure. Specifically, in the discharge valve, when the pressure in the space inside the cylinder connected to the inlet of the discharge valve increases as the piston of the booster pump moves, the ball, which serves as the valve body, pushes back the spring, opening the valve. This allows the fluid in the cylinder where the piston is located to be discharged outside the discharge valve. On the other hand, when the pressure in the space connected to the inlet of the discharge valve decreases as the piston of the booster pump moves, the ball is pushed by the spring, closing the valve. This prevents the fluid in the cylinder where the piston is located from being discharged through the discharge valve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4031807 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a discharge valve, the space in which a spring-like biasing member that biases the valve body is located is also filled with fluid. In the open state, the fluid in this space is pushed into the valve body, reducing the volume of the space and temporarily increasing the pressure. The fluid in the space then flows out through the outer periphery of the valve body to the discharge hole. In the closed state, the valve body is pushed back, increasing the volume of the space and temporarily decreasing the pressure. At this time, the fluid that had been remaining on the outer periphery of the valve body flows into the space.

[0005] As the valve disc moves, fluid flows out or in to the space. At this time, the flow of fluid into the space affects the movement of the valve disc. Specifically, if there is a large resistance when fluid flows out or in to the space, the movement of the valve disc will be slow. As a result, it will take a long time for the discharge valve to open or close. In particular, if it takes a long time to open, the pressure inside the cylinder of a booster pump may rise too much, or the pressure loss may increase in the open state, causing the internal pressure of the cylinder to exceed the allowable pressure or reach the operational interlock, resulting in a shutdown.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a discharge valve, a boost pump, and a hydrogen supply system that can reduce the load by shortening the time it takes to reach the open state. [Means for solving the problem]

[0007] In order to solve the above problems, a discharge valve according to the present disclosure includes a casing having a housing space portion in communication with a fluid inlet and a fluid discharge hole, the casing having a housing space portion in communication with the fluid discharge hole, a valve seat disposed in the housing space portion and having an inlet port in communication with the fluid inlet and a discharge port in communication with the fluid discharge hole, a valve element supported in the housing space portion so as to be movable between a closed position that closes the inlet port and an open position that opens the inlet port, and a valve element disposed in the housing space portion and having a valve element in communication with the inlet port and a valve element in communication with the valve element in the housing space portion. a valve seat pressing member that defines an arrangement space located on the opposite side thereof and that determines the position of the valve seat relative to the casing, and a biasing member that is disposed in the arrangement space and biases the valve body toward the closed position, the valve seat pressing member having a first communication hole that connects the arrangement space with the fluid discharge hole, and the first communication hole having a flow path shape that provides greater resistance to fluid flowing from the fluid discharge hole into the arrangement space than to fluid flowing out from the arrangement space to the fluid discharge hole.

[0008] In addition, the boost pump according to the present disclosure includes an intake valve that draws low-temperature fluid into a compression chamber, a piston that compresses the low-temperature fluid drawn into the compression chamber from the intake valve, and a discharge valve that discharges the low-temperature fluid compressed by the piston.

[0009] The hydrogen supply system according to the present disclosure also includes a compressor having the boost pump and compressing liquid hydrogen as a cryogenic fluid, an evaporator that vaporizes the liquid hydrogen compressed by the compressor, and a dispenser that supplies the hydrogen gas vaporized by the evaporator. [Effects of the Invention]

[0010] According to the discharge valve, boost pump, and hydrogen supply system of the present disclosure, the load can be reduced by shortening the time until the valve is opened. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram illustrating the overall configuration of a hydrogen supply system according to an embodiment of the present disclosure. [Figure 2] 1 is a schematic configuration diagram illustrating a compression device according to an embodiment of the present disclosure. [Figure 3] 1 is a cross-sectional view illustrating a main portion of a booster pump including a discharge valve according to an embodiment of the present disclosure. [Figure 4] FIG. 1 is a cross-sectional view showing a discharge valve according to a first embodiment of the present disclosure. [Figure 5] FIG. 2 is a cross-sectional view of a main portion showing a first communication hole according to the first embodiment of the present disclosure. [Figure 6] FIG. 10 is a cross-sectional view of a main portion showing a first communication hole according to a second embodiment of the present disclosure. [Figure 7] FIG. 10 is a cross-sectional view of a main portion showing a first communication hole according to a third embodiment of the present disclosure. [Figure 8] FIG. 10 is a cross-sectional view showing a discharge valve according to a fourth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] First Embodiment Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes configurations that combine the embodiments. Furthermore, the components in the embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially identical, and those that are within the so-called equivalent range.

[0013] <Hydrogen supply system> As shown in Fig. 1, a hydrogen supply system 10 supplies (replenishes) liquid hydrogen stored in a container 11 as hydrogen gas at a predetermined pressure to a power source of a vehicle 12. Here, the power source is, for example, a fuel cell or a hydrogen engine, and is mounted on the vehicle 12. The hydrogen supply system 10 is, for example, a so-called hydrogen filling station facility that supplies (replenishes) hydrogen gas, which is a fuel, to the power source of the vehicle 12. However, the hydrogen supply system 10 is not limited to supplying hydrogen gas to the power source of the vehicle 12, but may also compress and supply a cryogenic fluid (for example, liquid hydrogen, liquid nitrogen, liquid oxygen, liquefied carbon dioxide, liquefied natural gas, liquefied propane gas, etc.).

[0014] The hydrogen supply system 10 includes a compressor 21, an evaporator 22, and a dispenser 23. The compressor 21 compresses liquid hydrogen (low-temperature fluid) supplied from the container 11 to a predetermined high pressure (high-pressure state). The evaporator 22 generates hydrogen gas by vaporizing the high-pressure liquid hydrogen compressed by the compressor 21. The dispenser 23 fills the hydrogen gas generated by the evaporator 22 into the power source of the vehicle 12.

[0015] Although the compressor 21 compresses the liquid hydrogen stored in the container 11 to a predetermined high pressure, the configuration is not limited to this. For example, if the container 11 stores hydrogen gas, the compressor 21 may compress the hydrogen gas stored in the container 11 to a predetermined high pressure.

[0016] The compressor 21 has a drive motor 31 and a boost pump 32. The drive motor 31 is an electric motor that can be driven by power supplied from an external source. The rotation speed of the drive motor 31 is controlled by an inverter (not shown). The drive motor 31 transmits the rotational force to the boost pump 32. The boost pump 32 is operated by the rotational force of the drive motor 31.

[0017] <Compression device> As shown in Figure 2, the drive motor 31 is connected to the boost pump 32 via a reducer 33. The reducer 33 reduces the rotational force of the drive motor 31 and transmits it to the boost pump 32. The boost pump 32 is a reciprocating pump. The boost pump 32 operates by converting the rotational force of the drive motor 31, which has been reduced in speed by the reducer 33, into reciprocating power. The boost pump 32 uses the reciprocating power to alternately draw in and compress (boost) liquid hydrogen, compressing the drawn-in liquid hydrogen to a predetermined high-pressure state and discharging it to the outside.

[0018] The booster pump 32 includes a crank mechanism 34 , a crosshead 35 , a piston rod 36 , a piston 37 , and a cylinder block 38 .

[0019] The crank mechanism 34 converts the rotational force transmitted from the reducer 33 into linear reciprocating power and transmits it to the crosshead 35. The crosshead 35 reciprocates in the vertical direction VD due to the reciprocating power in the vertical direction VD transmitted from the crank mechanism 34. The upper end of the piston rod 36 is connected to the crosshead 35, and the other end is connected to a piston 37. The cylinder block 38 has a hollow shape, and the piston 37 is supported therein so as to be movable along the vertical direction VD.

[0020] The lower part of the booster pump 32, i.e., the cylinder block 38, is disposed inside the vessel 39. The vessel 39 is an insulated vacuum vessel, and the inside thereof is maintained in a vacuum state together with the booster pump 32. Liquid hydrogen is supplied inside the vessel 39.

[0021] When the boost pump 32 is activated, first, during the suction stroke when the piston 37 rises, liquid hydrogen in the container 39 is sucked into the cylinder block 38. Next, during the compression stroke when the piston 37 descends, the liquid hydrogen inside the cylinder block 38 is compressed, and high-pressure liquid hydrogen is discharged outside the container 39.

[0022] <Booster pump configuration> 3, boost pump 32 includes a suction valve 41 and a discharge valve 42. When opened, suction valve 41 draws liquid hydrogen into compression chamber 43. When opened, discharge valve 42 discharges high-pressure liquid hydrogen compressed in compression chamber 43 to the outside.

[0023] The cylinder block 38 is disposed along the vertical direction VD. The cylinder block 38 has a fitting hole 51 that opens upward formed in its upper part, and a recess 52 that opens downward formed in its lower part. The fitting hole 51 and the recess 52 are cylindrical and communicate with each other through a communication hole 53 that is also cylindrical. The piston 37 fits into the fitting hole 51 of the cylinder block 38 from above and is supported so as to be movable along the vertical direction VD. When the piston 37 fits into the fitting hole 51 of the cylinder block 38, a compression chamber 43 is formed, which is defined by the piston 37 and the fitting hole 51. The fitting hole 51, the recess 52, the communication hole 53, the piston 37, and the compression chamber 43 are concentrically disposed.

[0024] The suction valve 41 is disposed in the recess 52 of the cylinder block 38. The suction valve 41 includes a valve casing 61, a first valve body 62, a second valve body 63, and a retainer member 64.

[0025] The valve casing 61 has a convex cylindrical shape. The valve casing 61 has a small-diameter main body portion 61a and a flange portion 61b with a diameter larger than that of the main body portion 61a. The valve casing 61 is configured such that the flange portion 61b is integrally formed with the lower part of the main body portion 61a. The recess 52 has a small-diameter hole 52a and a large-diameter hole 52b with a diameter larger than that of the small-diameter hole 52a. The recess 52 is configured such that the large-diameter hole 52b is integrally disposed below the small-diameter hole 52a. The main body portion 61a of the valve casing 61 is fitted into the small-diameter hole 52a of the recess 52, and the flange portion 61b is fitted into the large-diameter hole 52b of the recess 52. In this configuration, the lower surface of the flange portion 61b of the valve casing 61 is continuous with the lower surface of the cylinder block 38 without any step. The length of the main body 61a of the valve casing 61 is shorter than the length of the small-diameter hole 52a, so that the tip surface of the main body 61a and the bottom surface of the small-diameter hole 52a face each other with a gap between them, thereby defining a space 71 between the recess 52 of the cylinder block 38 and the valve casing 61.

[0026] The valve casing 61 has a through hole 72 formed in the center along the vertical direction VD. The valve casing 61 also has a plurality of (six in this embodiment) suction holes 73 formed along the vertical direction VD at intervals in the circumferential direction on its radially outer peripheral side. The valve casing 61 also has a plurality of (eight in this embodiment) discharge holes 74 formed along the vertical direction VD at intervals in the circumferential direction on its radially inner side (the through hole 72 side). The suction holes 73 draw liquid hydrogen from the outside into the space 71. The discharge holes 74 discharge liquid hydrogen or hydrogen gas remaining in the space 71 to the outside. The "outside" here refers to the outside of the cylinder block 38, the inside of the container 39 (see FIG. 2), which is filled with liquid hydrogen at a low pressure of approximately atmospheric pressure to 1 MPaG.

[0027] The first valve body 62 has a main rod portion 62a and a head portion 62b. The first valve body 62 has a head portion 62b integrally formed at the upper end of the main rod portion 62a. The main rod portion 62a is disposed inside the valve casing 61 along the vertical direction VD. That is, the main rod portion 62a of the first valve body 62 is fitted into a through-hole 72 of the valve casing 61, and the first valve body 62 is supported so as to be movable along the axial direction (vertical direction VD). The head portion 62b is formed in a substantially truncated cone shape whose diameter increases upward. The flat upper surface of the head portion 62b of the first valve body 62 is a pressure-receiving surface 62c, and the curved lower surface of the head portion 62b is a seat surface 62d. The pressure-receiving surface 62c of the first valve body 62 faces the compression chamber 43.

[0028] Meanwhile, in the cylinder block 38, the upper portion of the communication hole 53 expands in diameter upward so as to have the same shape as the head portion 62b, and a main valve seat 53a is formed. The head portion 62b of the first valve body 62 is disposed above the communication hole 53. The seat surface 62d can be seated on the main valve seat 53a. When the first valve body 62 moves downward and the seat surface 62d of the head portion 62b seats on the main valve seat 53a, the communication hole 53 is closed, blocking communication between the compression chamber 43 and the space 71. On the other hand, when the first valve body 62 moves upward and the seat surface 62d of the head portion 62b moves away from the main valve seat 53a, the communication hole 53 is opened, connecting the compression chamber 43 and the space 71.

[0029] The first valve body 62 has a main rod portion 62a whose lower end protrudes downward from the valve casing 61. A spring receiving member 76 is fixed to the lower end of the main rod portion 62a by a nut 75. A pump compression coil spring 77 is disposed between a spring receiving portion 61c formed in the valve casing 61 and the spring receiving member 76 of the first valve body 62. The pump compression coil spring 77 biases the first valve body 62 downward with respect to the valve casing 61. That is, the biasing force of the pump compression coil spring 77 biases the first valve body 62 in a direction in which the seat surface 62d of the head portion 62b seats on the main valve seat 53a of the communicating hole 53, and the first valve body 62 is biased and supported in a position in which the communicating hole 53 is closed and the compression chamber 43 is isolated from the space 71.

[0030] The second valve body 63 is a disk-shaped plate-like member. An opening 63a is formed in the center of the second valve body 63. The outer diameter of the second valve body 63 is approximately the same as the outer diameter of the valve casing 61, and the inner diameter is larger than the diameter at the positions where the multiple discharge holes 74 are formed. The second valve body 63 is disposed in a space 71 defined between the recess 52 of the cylinder block 38 and the valve casing 61. The second valve body 63 is supported in the space 71 so as to be movable in the vertical direction VD relative to the cylinder block 38 and the valve casing 61. Ring-shaped seal members 81 and 82 are disposed between the second valve body 63 and the main body 61a of the valve casing 61. The seal member 81 is disposed on the outer periphery of the main body 61a. The seal member 82 is disposed on the inner periphery of the main body 61a. That is, the seal members 81, 82 are arranged on both radial sides of the main body 61a, sandwiching the multiple suction holes 73. The second valve body 63 has an upper surface that is a pressure-receiving surface 63b and a lower surface that is a seat surface 63c that contacts the seal members 81, 82. The pressure-receiving surface 63b of the second valve body 63 faces the communication hole 53. When the seat surface 63c of the second valve body 63 is seated on the seal members 81, 82, the space 71 is blocked from communicating with the multiple suction holes 73. On the other hand, when the seat surface 63c of the second valve body 63 is separated from the seal members 81, 82, the space 71 is communicated with the multiple suction holes 73.

[0031] The pressing member 64 is formed in a cylindrical shape. The pressing member 64 presses the valve casing 61 against the cylinder block 38. That is, the pressing member 64 has a plurality of mounting holes (not shown) aligned along the vertical direction VD and spaced apart in the circumferential direction. The upper surface of the pressing member 64 contacts the lower surface of the cylinder block 38 and the lower surface of the flange portion 61b of the valve casing 61. In this state, a plurality of fastening bolts 91 are inserted from below into the mounting holes of the pressing member 64, and their tip ends are threaded into threaded holes (not shown) in the cylinder block 38. By fastening the pressing member 64 to the cylinder block 38, the valve casing 61 is positioned in the recess 52 and pressed against the pressing member 64, and is supported by the cylinder block 38.

[0032] The pressing member 64 has an outer diameter that is approximately the same as the outer diameter of the cylinder block 38, and an inner diameter that is larger than the diameter at the positions where the multiple suction holes 73 are formed. Therefore, the lower end openings of the multiple suction holes 73 and the lower end openings of the multiple discharge holes 74 are exposed inside the pressing member 64. The multiple suction pipes 92 are supported by the pressing member 64 via a support member (not shown). One end of the multiple suction pipes 92 is connected to the lower end openings of the multiple suction holes 73, and the other end extends upward and opens to the outside, i.e., into the interior of the container 39 (see FIG. 2).

[0033] <Discharge valve configuration> The discharge valve 42 is a check valve and is disposed on the side of the cylinder block 38. An accommodation hole (accommodation space) 151 is formed inside the cylinder block 38. The accommodation hole 151 is formed along a radial direction (horizontal direction HD) perpendicular to the axial direction (vertical direction VD) of the cylinder block 38. The accommodation hole 151 forms a cylindrical space extending in the horizontal direction HD. The accommodation hole 151 has an external opening 152 that opens to the outside on one side in the horizontal direction HD. The external opening 152 is formed in the cylinder block 38. The external opening 152 connects the accommodation hole 151 to the outside of the cylinder block 38. The internal structure of the discharge valve 42 is positioned by being inserted into the accommodation hole 151 through the external opening 152. In other words, with respect to the discharge valve 42, a portion of the cylinder block 38 serves as a casing that forms an outer shell. The external opening 152 is closed by a closing member 153.

[0034] The cylinder block 38 has a fluid inlet hole 154 and an annular flow path (fluid discharge hole) 155. The fluid inlet hole 154 is formed in the cylinder block 38 so as to communicate with the compression chamber 43 on the other side of the horizontal direction HD relative to the discharge valve 42. The annular flow path 155 is formed in a ring shape on the outer periphery of the valve element 102, which will be described later. The annular flow path 155 is a discharge hole for hydrogen gas, and is connected to the outside of the cylinder block 38.

[0035] As shown in FIG. 4, the discharge valve 42 has a valve seat 101 , a valve element 102 , a valve seat pressing member 103 , a compression coil spring (biasing member) 104 , and a first communication hole 105 .

[0036] The valve seat 101 is formed in a cylindrical shape. The valve seat 101 is accommodated in the accommodation hole 151. The valve seat 101 is disposed inside the annular flow path 155, on the other side of the accommodation hole 151 in the horizontal direction HD. The other end of the valve seat 101 in the axial direction (horizontal direction HD) contacts the end face of the accommodation hole 151, and the outer circumferential surface of the valve seat 101 on the other side in the horizontal direction HD contacts the inner circumferential surface of the accommodation hole 151, thereby determining the axial and radial position of the valve seat 101 relative to the cylinder block 38. A ring-shaped seal member 121 is disposed on the other end of the valve seat 101 in the axial direction (horizontal direction HD). The seal member 121 seals by coming into close contact with the end face of the accommodation hole 151 (cylinder block 38).

[0037] The valve seat 101 has a valve seat accommodating hole 101a formed along its axial direction (horizontal direction HD). The valve seat accommodating hole 101a is open on one side in the axial direction. The valve seat 101 also has an inlet 113 communicating with the fluid inlet hole 154 and an outlet 114 communicating with the annular flow path 155. Specifically, the valve seat 101 has the inlet 113 formed on the other side in the horizontal direction HD and the outlet 114 formed radially outward therefrom. The inlet 113 is a hole formed at the center of the valve seat 101 along the horizontal direction HD. The inlet 113 communicates with the fluid inlet 154 and the valve seat accommodating hole 101a. The outlet 114 is a hole formed along the radial direction of the valve seat 101. A plurality of outlets 114 are formed at intervals around the circumferential direction of the valve seat 101. The discharge port 114 communicates the annular flow path 155 with the valve seat receiving hole 101a.

[0038] The valve body 102 has a ball 111 and a support 112. The support 112 is formed in a cylindrical shape. The support 112 has a receiving portion 112a and a rod portion 112b. The receiving portion 112a is capable of receiving the ball 111. The rod portion 112b is formed integrally with the receiving portion 112a on the opposite side of the ball 111. The support 112 is formed so that the outer diameter of the rod portion 112b is smaller than the outer diameter of the receiving portion 112a, thereby forming a step. The ball 111 is fitted into the receiving portion 112a and is capable of moving integrally with the support 112. Note that the ball 111 and the support 112 of the valve body 102 may be separate or integral.

[0039] The valve disc 102 is disposed in a valve seat receiving hole 101a of the valve seat 101. The valve disc 102 is supported relative to the valve seat 101 so as to be movable in the horizontal direction HD. The valve disc 102 is movable between a closed position where it closes an inlet 113 of the valve seat 101 and an open position where it opens the inlet 113. The closed position of the valve disc 102 is a position where the ball 111 is seated in close contact with the periphery of the inlet 113 of the valve seat 101. The open position of the valve disc 102 is a position where the ball 111 is separated from the inlet 113 of the valve seat 101.

[0040] The valve element 102 closes the discharge valve 42 when the ball 111 is brought into close contact with the periphery of the inlet 113 by the biasing force of the compression coil spring 104. As a result, liquid hydrogen in the compression chamber 43 cannot flow from the fluid inlet 154 through the inlet 113 into the interior of the discharge valve 42. Furthermore, when high-pressure liquid hydrogen from the compression chamber 43 acts on the inlet 113 through the fluid inlet 154, the valve element 102 moves backward against the biasing force of the compression coil spring 104, and the inlet 113 is opened. As a result, the liquid hydrogen in the compression chamber 43 flows from the fluid inlet 154 through the inlet 113 into the interior of the discharge valve 42 and is discharged from the discharge port 114 to the annular flow path 155.

[0041] The valve seat hold-down member 103 is formed in a cylindrical shape with one end closed in the horizontal direction HD. The valve seat hold-down member 103 has a tubular portion 103a, a partition wall portion 103b, and a threaded portion 103c. A hold-down member accommodating hole 103d is formed in the axial direction inside the tubular portion 103a. The partition wall portion 103b is integrally formed with the tubular portion 103a on one side in the horizontal direction HD, thereby closing the hold-down member accommodating hole 103d. The hold-down member accommodating hole 103d is open on the other side in the horizontal direction HD. The threaded portion 103c is formed on the outer peripheral surface of the tubular portion 103a. The threaded portion 103c screws into a block threaded portion 151a formed on the inner peripheral surface of the cylinder block 38, which forms the accommodating hole 151.

[0042] The valve seat hold-down member 103 is inserted into the accommodation hole 151 from the external opening 152, and by rotating the valve seat hold-down member 103, the threaded portion 103c screws into the block threaded portion 151a. When the valve seat hold-down member 103 is further rotated, the valve seat hold-down member 103 moves to the other side in the horizontal direction HD and stops when its tip abuts against the valve seat 101. Therefore, the valve seat hold-down member 103 is fixed to the cylinder block 38 at the position where its tip abuts against the valve seat 101. In addition, the valve seat 101 is also positioned and fixed to the cylinder block 38 by the valve seat hold-down member 103.

[0043] At this time, the valve seat 101 and the valve seat hold-down member 103 come into contact, so that the valve seat accommodating hole 101a of the valve seat 101 and the presser member accommodating hole 103d of the valve seat hold-down member 103 communicate with each other. Here, the inner diameter of the valve seat accommodating hole 101a of the valve seat 101 and the inner diameter of the presser member accommodating hole 103d of the valve seat hold-down member 103 are the same. In other words, an arrangement space 115, in which the valve seat accommodating holes 101a and the presser member accommodating holes 103d are connected, is defined between the valve seat 101 and the valve seat hold-down member 103. The valve element 102 is arranged so that the ball 111 is located in the valve seat accommodating hole 101a and the support body 112 spans from the valve seat accommodating hole 101a to the presser member accommodating hole 103d. In the support body 112, the outer diameter of the receiving portion 112a is slightly smaller than the inner diameter of the valve seat accommodating hole 101a of the valve seat 101. In addition, the support body 112 is formed so as to ensure a gap between the outer peripheral surface of the rod portion 112b and the inner peripheral surface of the presser member accommodating hole 103d of the valve seat presser member 103, through which the compression coil spring 104 is interposed.

[0044] The compression coil spring 104 is disposed in the arrangement space 115 on the opposite side of the inlet 113 with respect to the valve element 102, i.e., between the valve element 102 and the valve seat hold-down member 103. At this time, the compression coil spring 104 is disposed in the gap between the rod portion 112b of the support body 112 and the tubular portion 103a of the valve seat hold-down member 103. One end of the compression coil spring 104 presses against a step of the support body 112 of the valve element 102, and the other end presses against the inner surface of the partition portion 103b of the valve seat hold-down member 103. Therefore, the compression coil spring 104 biases the valve element 102 against the valve seat hold-down member 103 toward a closed position where the ball 111 closes the inlet 113.

[0045] The first communication hole 105 communicates between the arrangement space 115 and the annular flow path 155. The first communication hole 105 is formed to penetrate the valve seat holddown member 103 in the radial direction. A plurality of (for example, four) first communication holes 105 are arranged on the valve seat holddown member 103 at equal intervals in the circumferential direction. The first communication hole 105 is arranged at a position where it will not be blocked by the valve disc 102 in either a state where the valve disc 102 is separated from the valve seat 101 and the inlet 113 is opened (open state), or a state where the valve disc 102 is in contact with the valve seat 101 and the inlet 113 is closed (closed state). In other words, the first communication hole 105 communicates between the arrangement space 115 and the annular flow path 155 in both the open state and the closed state. The first communication hole 105 has a flow path shape that provides greater resistance to fluid flowing from the annular flow path 155 into the arrangement space 115 than to fluid flowing out from the arrangement space 115 to the annular flow path 155. The first communication hole 105 has the same shape around its entire circumference. Specifically, as shown in FIG. 5 , the first communication hole 105 of the first embodiment has a communicating inner opening 210, a communicating outer opening 220, and a flow path forming surface 230.

[0046] The communicating internal opening 210 is formed facing the arrangement space portion 115. In other words, the communicating internal opening 210 faces the space inside the valve seat hold-down member 103. The communicating internal opening 210 is formed and connected to the inner circumferential surface of the valve seat hold-down member 103. The communicating internal opening 210 is located at a corner formed by the flow path forming surface 230 and the inner circumferential surface of the valve seat hold-down member 103. The communicating internal opening 210 is connected perpendicularly to the inner circumferential surface of the valve seat hold-down member 103. The communicating internal opening 210 has the same shape around the entire circumference of the first communicating hole 105.

[0047] The communicating external opening 220 is formed facing the annular flow path 155. In other words, the communicating external opening 220 faces the space outside the valve seat holddown member 103. The communicating external opening 220 is formed and connected to the outer peripheral surface of the valve seat holddown member 103. The communicating external opening 220 is located at a corner formed by the flow path forming surface 230 and the outer peripheral surface of the valve seat holddown member 103. The flow path cross-sectional area of the communicating external opening 220 is larger than that of the communicating internal opening 210. The flow path cross-sectional area of the communicating external opening 220, when viewed from the radial direction of the valve seat holddown member 103, is larger than that of the communicating internal opening 210. The communicating external opening 220 is formed with a curved surface such that the flow path cross-sectional area gradually increases. The communicating external opening 220 is formed with a convex curved surface such that the flow path cross-sectional area gradually increases from the inner peripheral surface of the valve seat holddown member 103 toward the outer peripheral surface. The communicating external opening 220 is formed, for example, by R-chamfering the outer peripheral surface of the valve seat hold-down member 103 and the flow path forming surface 230. Therefore, the communicating external opening 220 is formed so that the flow path cross-sectional area is widest at the position closest to the outer peripheral surface of the valve seat hold-down member 103.

[0048] The flow path forming surface 230 connects the communicating inner opening 210 and the communicating outer opening 220. The flow path forming surface 230 is a smooth surface that extends in the radial direction of the valve seat hold-down member 103 from the communicating inner opening 210 to the communicating outer opening 220. The flow path forming surface 230 in this embodiment extends straight and perpendicular to the inner and outer circumferential surfaces of the valve seat hold-down member 103.

[0049] As shown in FIG. 4 , the accommodation hole 151 opens to the outside through an external opening 152. The external opening 152 has an inner diameter larger than that of the accommodation hole 151. The closing member 153 is cylindrical and has a closing thread 153a formed on its outer circumferential surface. The closing thread 153a of the closing member 153 is threadedly engaged with an opening thread 152a formed on the inner circumferential surface of the external opening 152. A ring-shaped seal member 122 is disposed at one end of the closing member 153 in the axial direction (horizontal direction HD), and seals the accommodation hole 151 (cylinder block 38) by closely contacting the end face of the accommodation hole 151. Therefore, a sealed space 116 is defined between the valve seat hold-down member 103 and the closing member 153 at the accommodation hole 151 and the external opening 152. The sealed space 116 is connected to the outside of the cylinder block 38.

[0050] <Booster pump operation> Next, the operating state of the boost pump 32 will be described with reference to FIG. 3. First, during the suction stroke of the boost pump 32, when the piston 37 moves (rises) from the bottom dead center to the top dead center via the piston rod 36, the volume of the compression chamber 43 expands, and the pressure in the compression chamber 43 becomes negative. At this time, the upward force (suction force) of the first valve body 62 overcomes the biasing force of the pump compression coil spring 77, and the seat surface 62d of the head portion 62b moves upward, separating from the main valve seat 53a. The first valve body 62 then opens the communication hole 53, thereby connecting the compression chamber 43 to the space 71. Furthermore, when the negative pressure in the compression chamber 43 acts on the second valve body 63 through the communication hole 53, the second valve body 63 moves upward due to the negative pressure, and the seat surface 63c moves away from the seal members 81 and 82. The second valve body 63 then connects the space 71 to each suction hole 73. Therefore, suction valve 41 draws external liquid hydrogen from each suction pipe 92 through each suction hole 73 into space 71 , and further through communication hole 53 into compression chamber 43 .

[0051] Next, during the compression stroke of the boost pump 32, when the piston 37 moves (descends) via the piston rod 36 to the top dead center or bottom dead center, the volume of the compression chamber 43 decreases, and the pressure in the compression chamber 43 becomes positive. At this time, the suction force of the first valve body 62 decreases, and the first valve body 62 moves downward due to the biasing force of the pump compression coil spring 77, so that the seat surface 62d of the head portion 62b seats on the main valve seat 53a. The first valve body 62 then closes the communication hole 53, thereby isolating the compression chamber 43 from the space 71. Furthermore, when the positive pressure in the compression chamber 43 acts on the second valve body 63 through the communication hole 53, the suction force decreases, and the second valve body 63 moves downward, so that the seat surface 63c seats on the seal members 81 and 82. The second valve body 63 then blocks the space 71 from each suction hole 73.

[0052] As the piston 37 moves further downward, the volume of the compression chamber 43 is further reduced, causing the pressure in the compression chamber 43 to increase. At this time, when the pressure of the liquid hydrogen in the compression chamber 43 reaches or exceeds a predetermined high pressure, the pressure of the liquid hydrogen exceeds the biasing force of the compression coil spring 104, causing the valve element 102 to move backward and opening the inlet 113. The liquid hydrogen in the compression chamber 43 then flows from the fluid inlet hole 154 through the inlet 113 into the discharge valve 42, and is discharged from the discharge port 114 into the annular flow path 155 and to the outside of the cylinder block 38.

[0053] During the compression stroke of booster pump 32, first valve body 62 descends and seat surface 62d of head portion 62b seats on main valve seat 53a to close communication hole 53, during which time some of the high-pressure liquid hydrogen in compression chamber 43 leaks through communication hole 53 into space 71. The high-pressure liquid hydrogen that has leaked into space 71 is discharged through each discharge hole 74 into the interior of container 39 (see FIG. 2), which is at atmospheric pressure.

[0054] <Discharge valve operation> Next, the operating state of the discharge valve will be explained in more detail with reference to Figure 4. When the pressure in the compression chamber 43 (see Figure 3) becomes high due to the compression stroke of the boost pump 32, the high pressure acts on the ball 111 of the valve element 102. As a result, the valve element 102 moves backward against the biasing force of the compression coil spring 104, and the inlet 113 is opened. With the inlet 113 opened, liquid hydrogen in the compression chamber 43 flows from the fluid inlet hole 154 through the inlet 113 into the discharge valve 42. The liquid hydrogen that has flowed into the discharge valve 42 is discharged from the outlet 114 into the annular flow path 155 and then out of the cylinder block 38.

[0055] At this time, the valve element 102 moves backward and compresses the compression coil spring 104, reducing the volume of the arrangement space 115 and increasing the pressure, causing the liquid hydrogen remaining in the arrangement space 115 to flow through the outer periphery of the valve element 102 to the discharge port 114. However, the discharge valve 42 of this embodiment is formed with a first communication hole 105 that connects the arrangement space 115 to the annular flow path 155. Therefore, when the volume of the arrangement space 115 decreases and the pressure increases, the liquid hydrogen remaining in the arrangement space 115 is pushed out not only through the discharge port 114, but also from the arrangement space 115 through the first communication hole 105 to the annular flow path 155.

[0056] Furthermore, when the pressure in the compression chamber 43 (see FIG. 3) decreases due to the suction stroke of the boost pump 32, the pressure acting on the ball 111 decreases, and the valve element 102 moves forward without resisting the biasing force of the compression coil spring 104, thereby closing the inlet port 113. Closing the inlet port 113 stops the outflow of liquid hydrogen from the discharge valve 42 to the outside of the cylinder block 38.

[0057] At this time, the valve element 102 moves forward, stretching the compression coil spring 104, increasing the volume of the arrangement space 115 and decreasing the pressure. As a result, the liquid hydrogen remaining in the annular flow path 155 flows through the first communication hole 105 and returns to the arrangement space 115.

[0058] (Action and effect) In the discharge valve 42 configured as described above, and the boost pump 32 and hydrogen supply system 10 including such a discharge valve 42, when the inlet 113 is opened, liquid hydrogen remaining in the arrangement space 115 is forced out from the arrangement space 115 through the first communication hole 105 and into the annular flow path 155. At that time, the liquid hydrogen flows in this order through the communication inner opening 210, the flow path forming surface 230, and the communication outer opening 220, and is then discharged into the annular flow path 155. As a result, the flow of liquid hydrogen from the arrangement space 115 to the discharge port 114 is reduced, preventing the valve element 102 from being hindered in its retracting movement and preventing damage to the valve element 102 due to cavitation erosion.

[0059] In addition, in the first communication hole 105, the liquid hydrogen that has been stationary in the arrangement space 115, the first communication hole 105, and the annular flow path 155 begins to move rapidly the moment the inlet 113 is opened. At this time, the resistance to the fluid flowing from the annular flow path 155 into the arrangement space 115 due to the communicating inner opening 210 is greater than the resistance to the fluid flowing from the arrangement space 115 to the annular flow path 155 due to the communicating outer opening 220. As a result, the balance of static friction forces of the flow from the arrangement space 115 through the first communication hole 105 to the annular flow path 155 is likely to be disrupted the moment the inlet 113 is opened. In other words, the liquid hydrogen that has been stationary in the first communication hole 105 is likely to escape from the communicating outer opening 220 to the annular flow path 155. Therefore, the liquid hydrogen can be smoothly pushed out through the first communication hole 105 into the annular flow path 155 the moment the inlet 113 is opened. As described above, at the moment the inlet 113 is opened, the liquid hydrogen in the first communication hole 105 behaves like an incompressible fluid and quickly flows out into the annular flow path 155, entraining the liquid hydrogen in the arrangement space 115. Therefore, discharge from the arrangement space 115 to the annular flow path 155 via the first communication hole 105 can be quickly performed. As a result, the timing at which the pressure in the arrangement space 115 reaches its peak is almost identical to the timing at which the inlet 113 is opened. This allows the discharge valve 42 to be quickly opened. This prevents the pressure inside the valve seat holding member 103 from exceeding the allowable pressure or reaching an operational interlock, which would cause the discharge valve 42 to shut down. This shortens the time it takes for the discharge valve 42 to open, thereby reducing the load.

[0060] Furthermore, in the first communication hole 105, the flow path cross-sectional area of the communicating outer opening 220 is larger than the flow path cross-sectional area of the communicating inner opening 210. This reduces static friction at the communicating outer opening 220. As a result, the ease of movement of liquid hydrogen at the communicating outer opening 220 at the moment the inlet 113 is opened can be ensured without placing any mechanical structure on the first communication hole 105. This makes it possible to quickly discharge liquid hydrogen from the first communication hole 105 through the communicating outer opening 220 to the annular flow path 155 at the moment the first communication hole 105 is opened, with a simple structure that differs only in the shape of the first communication hole 105. This reduces the load on the discharge valve 42 by shortening the time it takes to open.

[0061] Furthermore, the communicating outer opening 220 is formed as a curved surface by rounding off the corner formed by the flow path forming surface 230 and the outer peripheral surface of the valve seat hold-down member 103. Therefore, the communicating outer opening 220, which has a larger flow path cross-sectional area than the communicating inner opening 210, can be easily formed in the first communicating hole 105.

[0062] Second Embodiment Next, a discharge valve 42A according to a second embodiment of the present disclosure will be described. In the second embodiment described below, components common to the above embodiment will be denoted by the same reference numerals in the drawings, and description thereof will be omitted. In the second embodiment, the shape of the first communication hole 105A is different from that of the above embodiment.

[0063] 6, the first communication hole 105A of the second embodiment has an inclined surface 232. The first communication hole 105A has a communication inner opening 210, a communication outer opening 220, and a flow path forming surface 230A.

[0064] The flow path forming surface 230A connects the communicating inner opening 210 and the communicating outer opening 220. The flow path forming surface 230A has a vertical surface 231 and an inclined surface 232.

[0065] The vertical surface 231 is a smooth surface extending from the communicating inner opening 210. In this embodiment, the vertical surface 231 extends straight and perpendicular to the inner and outer circumferential surfaces of the valve seat holding member 103.

[0066] The inclined surface 232 is inclined so as to gradually widen from the communicating inner opening 210 toward the communicating outer opening 220. The inclined surface 232 extends from the vertical surface 231 to the communicating outer opening 220. The inclined surface 232 is inclined with respect to the vertical surface 231 at an inclination angle of, for example, 8° or less. The inclination angle of the inclined surface 232 with respect to the vertical surface 231 is preferably within a range of 4° to 8°. In other words, the inclined surface 232 widens from the vertical surface 231 so that the flow path cross-sectional area in the region where the vertical surface 231 is formed gradually widens all the way to the communicating outer opening 220. In other words, in the first communication hole 105A, the flow path cross-sectional area increases in the order of the communicating inner opening and vertical surface 231, the inclined surface 232, and the communicating outer surface.

[0067] (Action and effect) In the discharge valve 42A of the second embodiment, an inclined surface 232 is formed on the flow path forming surface 230A. Therefore, the flow path cross-sectional area of the region where the inclined surface 232 is formed expands toward the outer periphery at a constant angle from the flow path cross-sectional area of the communicating inner opening 210 so as to approach the flow path cross-sectional area of the communicating outer opening 220, thereby increasing the flow path cross-sectional area. The formation of such an inclined surface 232 reduces the normal stress acting on the liquid hydrogen in the first communication hole 105. As a result, the balance of static friction forces of the flow from the first communication hole 105 to the annular flow path 155 is more likely to be disrupted at the moment the inlet 113 is opened. In other words, the inclined surface 232 makes it easier for liquid hydrogen stationary in the first communication hole 105 to escape into the annular flow path 155. Therefore, at the moment the inlet 113 is opened, liquid hydrogen can be smoothly pushed through the first communication hole 105 into the annular flow path 155. In this way, at the moment the inlet 113 is opened, the liquid hydrogen in the first communication hole 105 behaves like an incompressible fluid, and quickly flows out into the annular flow path 155, dragging along the liquid hydrogen in the arrangement space 115. This further shortens the time it takes for the discharge valve 42 to open, thereby reducing the load on the discharge valve 42.

[0068] Furthermore, at the moment the inlet 113 is closed, liquid hydrogen remaining in the arrangement space 115, the first communication hole 105, and the annular passage 155 rapidly moves from the annular passage 155 through the first communication hole 105 to the arrangement space 115. At this time, as viewed from the fluid discharge hole, the inclined surface 232 narrows the passage cross-sectional area from the passage cross-sectional area of the communicating outer opening 220 toward the outer periphery at a certain angle so as to approach the passage cross-sectional area of the communicating inner opening 210, thereby reducing the passage cross-sectional area. As a result, at the moment the inlet 113 is closed, liquid hydrogen being forced out of the annular passage 155 through the first communication hole 105 and into the arrangement space 115 is less likely to escape from the communicating inner opening 210. This becomes more pronounced as the area where the inclined surface 232 is formed increases. Therefore, at the moment the inlet 113 is closed, liquid hydrogen cannot be smoothly forced out of the arrangement space 115 through the first communication hole 105. Therefore, there is a slight difference in the timing of discharge from the arrangement space 115 to the annular flow path 155 through the first communication hole 105 relative to the moment the inlet 113 is closed. As a result, the timing at which the pressure in the arrangement space 115 reaches its peak is later than when the inlet 113 is opened relative to the timing at which the inlet 113 is closed. This allows the discharge valve 42 to be closed more gradually than when it is opened. As a result, the time until the discharge valve 42 is opened is lengthened, which can alleviate the collision load when the valve element 102 comes into contact with the valve seat 101 and reduce the risk of damage to the contact portions between the valve seat 101 and the valve element 102.

[0069] In this way, the inclined surface 232 can make the resistance to the fluid passing through the first communication hole 105 asymmetric between the open state and the closed state. Therefore, not only the communication external opening 220 but also the inclined surface 232 can change the timing at which the static friction force at the start of movement of stationary liquid hydrogen is broken between the open state and the closed state. As a result, with a simple structure that only differs in the shape of the first communication hole 105A, it is possible to control the transient flow through the first communication hole 105A between the open state and the closed state, shorten the time it takes for the discharge valve 42 to start opening, and lengthen the time it takes for the discharge valve 42 to start closing.

[0070] Furthermore, the inclined surface 232 is inclined at an angle of, for example, 8° or less with respect to the vertical surface 231. Therefore, when switching between the open state and the closed state, once the liquid hydrogen starts to flow, separation of the liquid hydrogen flowing along the inclined surface 232 can be suppressed. By suppressing separation in this way, the first communication hole 105A, in which the inclined surface 232 is formed, can ensure a discharge flow rate while minimizing the steady-state pressure loss of a gradually expanding pipe. As a result, even if the inclined surface 232 is formed, it is possible to ensure that the opening operation of the discharge valve 42 is not hindered.

[0071] In the second embodiment, the communicating external opening 220 is not limited to a structure formed as a convex curved surface by R-chamfering. For example, if the first communicating hole 105A has an inclined surface 232, the communicating external opening 220 may be connected perpendicular to the outer peripheral surface of the valve seat hold-down member 103.

[0072] Third Embodiment Next, a discharge valve 42B according to a third embodiment of the present disclosure will be described. In the third embodiment described below, components common to the first and second embodiments will be denoted by the same reference numerals in the drawings, and description thereof will be omitted. In the third embodiment, the shape of the first communication hole 105B is different from those of the first and second embodiments.

[0073] As shown in FIG. 7, the first communication hole 105B of the third embodiment has a communication inner opening 210, a communication outer opening 220B, a flow path forming surface 230, and at least one step portion 240.

[0074] The communicating external opening 220B is formed facing the annular flow path 155. The communicating external opening 220B is formed as a convex curved surface such that the flow path cross-sectional area gradually increases from the inner peripheral surface to the outer peripheral surface of the valve seat holddown member 103. The communicating external opening 220B is formed, for example, by R-chamfering the outer peripheral surface of the valve seat holddown member 103, which has a smaller diameter than the communicating external opening 220 of the first embodiment, and the flow path forming surface 230.

[0075] The step portion 240 is disposed between the communicating inner opening 210 and the communicating outer opening 220B. At least one step portion 240 (three in this embodiment) is disposed for each first communicating hole 105B. The multiple step portions 240 are all formed with the same shape. Each step portion 240 has a protruding surface 241 and a reverse inclined surface 242.

[0076] The protruding surface 241 protrudes perpendicularly inward from the flow path forming surface 230. Therefore, when viewed from the communicating external opening 220, the protruding surface 241 is a flat surface formed in an annular shape.

[0077] The reverse inclined surface 242 is inclined so that the flow path cross-sectional area increases from the protruding surface 241 toward the communicating internal opening 210. The reverse inclined surface 242 is connected to the protruding surface 241 at an acute angle. The reverse inclined surface 242 is inclined at an inclination angle of 20° or less with respect to the flow path forming surface 230. In other words, the reverse inclined surface 242 increases in diameter from the protruding surface 241 to the wide flow path diameter inclined surface so that the flow path cross-sectional area in the region where the reverse inclined surface 242 is formed gradually increases toward the communicating internal opening 210. Furthermore, the connecting portion between the reverse inclined surface 242 and the protruding surface 241 is formed in a convex curved shape.

[0078] (Action and effect) In the discharge valve 42B of the third embodiment, a step portion 240 is formed between the communicating internal opening 210 and the communicating external opening 220B. The step portion 240 has a protruding surface 241 and an inclined surface 242 that form multiple flow paths that gradually narrow and then rapidly widen when the fluid flows from the communicating internal opening 210 to the communicating external opening 220B. On the other hand, the step portion 240 has a protruding surface 241 and an inclined surface 242 that form multiple flow paths that rapidly narrow and then gradually widen when the fluid flows from the communicating external opening 220B to the communicating internal opening 210. Therefore, once liquid hydrogen begins to flow from the communicating internal opening 210 to the communicating external opening 220B, a series of gradually narrowing flow paths with low pressure loss are formed, and the wall shear force of the main flow is reduced due to cavity flow. As a result, flow path resistance to the flowing liquid hydrogen can be reduced. Therefore, the discharge from the arrangement space portion 115 to the annular flow path 155 can be performed quickly through the first communication hole 105B.

[0079] Furthermore, once liquid hydrogen begins to flow from the communicating outer opening 220B to the communicating inner opening 210, the flowing liquid hydrogen first flows through a flow path that is abruptly narrowed by the protruding surface 241, and then flows through a flow path that is gradually widened by the inverted inclined surface 242. As a result, in the first communicating hole 105B, the resistance to liquid hydrogen flowing from the annular flow path 155 to the arrangement space 115 is greater than the resistance to liquid hydrogen flowing from the arrangement space 115 to the annular flow path 155. Therefore, the first communicating hole 105B can gradually discharge liquid hydrogen from the annular flow path 155 to the arrangement space 115. This makes it possible to control the flow rate difference between the outflow and inflow of liquid hydrogen through the first communicating hole 105B so that it is significantly asymmetric. This shortens the time until the opening state and lengthens the time until the closing state, thereby reducing the load.

[0080] The step portion 240 of the third embodiment is not limited to a structure in which the connecting portion between the reverse inclined surface 242 and the protruding surface 241 is formed in a convex curved shape. The step portion 240 may have a structure in which the connecting portion between the reverse inclined surface 242 and the protruding surface 241 is connected at an acute angle.

[0081] <Fourth embodiment> Next, a discharge valve 42C according to a fourth embodiment of the present disclosure will be described. In the fourth embodiment described below, components common to the first to third embodiments will be denoted by the same reference numerals in the drawings, and description thereof will be omitted. The fourth embodiment differs from the first to third embodiments in that the discharge valve 42C further includes a second communication hole 106.

[0082] As shown in FIG. 8, a discharge valve 42C of the fourth embodiment further includes a second communication hole .

[0083] The second communication hole 106 communicates the sealed space 116 with the arrangement space 115. The second communication hole 106 is formed to penetrate the partition wall 103b of the valve seat pressing member 103 in the horizontal direction HD. The second communication hole 106 extends straight in the horizontal direction HD. The second communication passage is formed on the opposite side of the valve body 102 from the valve seat 101. The second communication hole 106 communicates with the arrangement space 115 at a position that does not overlap with the valve body 102 and the compression coil spring 104. In other words, the second communication passage is formed in a position that is always open, regardless of the movement of the valve body 102 and the compression coil spring 104 that accompanies the opening and closing of the discharge valve 42C.

[0084] When the pressure of the liquid hydrogen acts on the ball 111 of the valve element 102, the valve element 102 moves backward against the biasing force of the compression coil spring 104, opening the inlet port 113. Then, the liquid hydrogen in the compression chamber 43 flows from the fluid inlet hole 154 through the inlet port 113 into the discharge valve 42C, is discharged from the discharge port 114 into the annular flow path 155, and is then discharged through the discharge hole.

[0085] At this time, the volume of the arrangement space 115 decreases due to the retraction of the valve element 102, and liquid hydrogen remaining in the arrangement space 115 is pushed out from the arrangement space 115 through the first communication hole 105 to the annular flow path 155. Furthermore, liquid hydrogen remaining in the arrangement space 115 is pushed out through the second communication passage to the sealed space 116. The second communication passage is formed in a position that does not overlap with the valve element 102 and the compression coil spring 104. Therefore, regardless of the movement of the valve element 102 and the compression coil spring 104, liquid hydrogen remaining in the arrangement space 115 can continue to be discharged into the sealed space 116 via the second communication hole 106.

[0086] (Other embodiments) The above describes in detail the embodiments of the present disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present disclosure.

[0087] The discharge valves 42, 42A, 42B, 42C, boost pump 32, and hydrogen supply system 10 are not limited to structures that circulate liquid hydrogen as a fluid as in this embodiment, but may circulate other liquids such as water. Furthermore, the fluid circulating in the discharge valves 42, 42A, 42B, 42C, boost pump 32, and hydrogen supply system 10 is not limited to liquid, but may be a gas such as steam.

[0088] Furthermore, the discharge valves 42, 42A, 42B, and 42C are not limited to being integral with the boost pump 32 as in this embodiment. The discharge valves 42, 42A, 42B, and 42C may be applied to devices or systems independent of the boost pump 32 and the hydrogen supply system 10.

[0089] Furthermore, the discharge valves 42, 42A, 42B, and 42C are not limited to a structure in which the casing is formed by a part of the cylinder block 38. The discharge valve 42 may have an independent casing that is detachable from the cylinder block 38.

[0090] Furthermore, the first communication holes 105, 105A, 105B are not limited to the structure of this embodiment. Therefore, the first communication holes 105, 105A, 105B are not limited to the structure having the communicating inner opening 210, the communicating outer opening 220, and the flow path forming surfaces 230, 230A shaped as in this embodiment. For example, the communicating inner opening 210 may be formed as a curved surface with a smaller radius of curvature than the communicating outer opening 220. Furthermore, the positions at which the first communication holes 105, 105A, 105B are formed are not limited to positions that radially penetrate the cylindrical portion 103a, as in this embodiment. The positions at which the first communication holes 105, 105A, 105B are formed may be positions that penetrate the partition wall portion 103b in the horizontal direction HD, like the second communication hole 106.

[0091] Furthermore, the second communication hole 106 is not limited to the structure of this embodiment. For example, the second communication hole 106 may have a communicating inner opening 210 or a communicating outer opening 220 shaped like the first communication holes 105, 105A, and 105B, or a flow path forming surface 230 or 230A. Furthermore, the second communication hole 106 is not limited to a structure in which it is formed together with the first communication holes 105, 105A, and 105B, and may be formed independently in the valve seat hold-down member 103.

[0092] <Additional Notes> The discharge valves 42, 42A, 42B, and 42C, the boost pump 32, and the hydrogen supply system 10 described in each embodiment can be understood, for example, as follows.

[0093] (1) Discharge valves 42, 42A, 42B, and 42C according to a first aspect include a casing having a housing space portion in communication with a fluid inlet hole 154 and a fluid outlet hole, the casing having a housing space portion in communication with the fluid outlet hole, a valve seat 101 disposed in the housing space portion and having an inlet 113 in communication with the fluid inlet hole 154 and an outlet 114 in communication with the fluid outlet hole, a valve element 102 supported in the housing space portion so as to be movable between a closed position for closing the inlet 113 and an open position for opening the inlet 113, and a valve element 102 disposed in the housing space portion and positioned on the opposite side of the inlet 113 from the valve element 102 in the housing space portion. The valve seat holding member 103 has a first communication hole 105, 105A, 105B that connects the arrangement space 115 with the fluid discharge hole, and the first communication hole 105, 105A, 105B has a flow path shape that provides greater resistance to the fluid flowing from the fluid discharge hole into the arrangement space 115 than to the fluid flowing out from the arrangement space 115 to the fluid discharge hole.

[0094] With this configuration, in the first communication hole 105, the liquid hydrogen that has been stationary in the arrangement space 115, the first communication hole 105, and the fluid discharge hole begins to move rapidly the moment the inlet 113 is opened. At this time, the resistance to the fluid flowing from the arrangement space 115 to the fluid discharge hole is greater than the resistance to the fluid flowing from the arrangement space 115 to the fluid discharge hole. As a result, the balance of static friction forces of the flow from the arrangement space 115 through the first communication hole 105 toward the fluid discharge hole is easily disrupted the moment the inlet 113 is opened. In other words, the liquid hydrogen that has been stationary in the first communication hole 105 is easily released into the fluid discharge hole. Therefore, the liquid hydrogen can be smoothly pushed out through the first communication hole 105 and into the fluid discharge hole the moment the inlet 113 is opened. In this way, at the moment the inlet 113 is opened, the liquid hydrogen in the first communication hole 105 behaves like an incompressible fluid, and quickly flows out to the fluid discharge hole, entraining the liquid hydrogen in the arrangement space 115. Therefore, the first communication hole 105 can quickly discharge the fluid from the arrangement space 115 to the fluid discharge hole. As a result, there is almost no difference between the timing at which the pressure in the arrangement space 115 reaches its peak and the timing at which the inlet 113 is opened. This allows the discharge valve 42 to be quickly opened. This shortens the time it takes for the discharge valve 42 to open, thereby reducing the load.

[0095] (2) The discharge valves 42, 42A, 42C according to the second aspect are the discharge valves 42, 42A, 42C of (1), wherein the first communication holes 105, 105A have a communicating inner opening 210 facing the arrangement space 115, a communicating outer opening 220 facing the fluid discharge hole, and a flow path forming surface 230, 230A connecting the communicating inner opening 210 and the communicating outer opening 220, and the flow path cross-sectional area of the communicating outer opening 220 is larger than the flow path cross-sectional area of the communicating inner opening 210.

[0096] With this configuration, it is possible to weaken the static friction force at the communicating external opening 220. As a result, it is possible to ensure the ease of movement of liquid hydrogen at the communicating external opening 220 the moment the inlet 113 is opened, without arranging any mechanical structure for the first communicating hole 105. As a result, with a simple structure that changes only the shape of the first communicating hole 105, it is possible to quickly discharge liquid hydrogen in the first communicating hole 105 from the communicating external opening 220 to the fluid discharge hole the moment it is opened. As a result, with a simple structure, it is possible to reduce the load on the discharge valve 42 by shortening the time it takes to open.

[0097] (3) The discharge valves 42, 42A, 42C according to the third aspect are the discharge valves 42, 42A, 42C of (2), in which the communicating external opening 220 is located at the corner formed by the flow path forming surface 230, 230A and the outer peripheral surface of the valve seat pressing member 103, and is formed with a curved surface that gradually increases the cross-sectional area of the flow path.

[0098] According to this configuration, the communicating outer opening 220 having a larger flow path cross-sectional area than the communicating inner opening 210 can be easily formed in the first communicating hole 105, 105A.

[0099] (4) The discharge valve 42A according to the fourth aspect is the discharge valve 42A of (2) or (3), wherein the flow path forming surface 230A has an inclined surface 232 that gradually widens from the communicating inner opening 210 toward the communicating outer opening 220.

[0100] With this configuration, the cross-sectional area of the region where the inclined surface 232 is formed expands from the cross-sectional area of the communicating inner opening 210 toward the outer periphery at a certain angle so as to approach the cross-sectional area of the communicating outer opening 220, thereby increasing the cross-sectional area of the flow path. The formation of this inclined surface 232 reduces the normal stress acting on the liquid hydrogen within the first communicating hole 105. As a result, the balance of static friction forces of the flow from the first communicating hole 105 toward the fluid discharge hole is more likely to be disrupted at the moment the inlet 113 is opened. In other words, the inclined surface 232 makes it easier for liquid hydrogen stationary within the first communicating hole 105 to escape to the fluid discharge hole. Therefore, at the moment the inlet 113 is opened, liquid hydrogen can be smoothly pushed out through the first communicating hole 105 and into the fluid discharge hole. In this way, at the moment the inlet 113 is opened, the liquid hydrogen in the first communication hole 105 behaves like an incompressible fluid, and quickly flows out into the annular flow path 155, dragging along the liquid hydrogen in the arrangement space 115. This further shortens the time it takes for the discharge valve 42 to open, thereby reducing the load on the discharge valve 42.

[0101] Furthermore, at the moment the inlet 113 is closed, liquid hydrogen remaining in the arrangement space 115, the first communication hole 105, and the fluid discharge hole rapidly moves from the fluid discharge hole through the first communication hole 105 to the arrangement space 115. At this time, when viewed from the fluid discharge hole, the inclined surface 232 narrows the flow path cross-sectional area from the flow path cross-sectional area of the communicating outer opening 220 toward the outer periphery at a certain opening angle so as to approach the flow path cross-sectional area of the communicating inner opening 210, thereby reducing the flow path cross-sectional area. As a result, at the moment the inlet 113 is closed, liquid hydrogen is difficult to escape from the communicating inner opening 210 as it is forced from the fluid discharge hole through the first communication hole 105 to the arrangement space 115. Therefore, at the moment the inlet 113 is closed, liquid hydrogen cannot be smoothly forced out through the first communication hole 105 into the arrangement space 115. Therefore, there is a slight difference in the timing of discharge from the arrangement space 115 to the fluid discharge hole through the first communication hole 105 relative to the moment the inlet 113 is closed. As a result, the timing at which the pressure peaks in the arrangement space 115 is later than when the inlet 113 is closed compared to when it is opened. This allows the discharge valve 42 to be closed more gradually than when it is opened. As a result, the time until the discharge valve 42 is opened is lengthened, which can alleviate the collision load when the valve element 102 comes into contact with the valve seat 101 and reduce the risk of damage to the contacting portions of the valve seat 101 and the valve element 102.

[0102] In this way, the inclined surface 232 can make the resistance to the fluid passing through the first communication hole 105 asymmetric between the open state and the closed state. Therefore, not only the communication external opening 220 but also the inclined surface 232 can change the timing at which the static friction force at the start of movement of stationary liquid hydrogen is broken between the open state and the closed state. As a result, with a simple structure that only differs in the shape of the first communication hole 105A, it is possible to control the transient flow through the first communication hole 105A between the open state and the closed state, shorten the time it takes for the discharge valve 42 to start opening, and lengthen the time it takes for the discharge valve 42 to start closing.

[0103] (5) A discharge valve 42B according to a fifth aspect is a discharge valve 42B according to any one of (1) to (4), wherein the first communication hole 105B has a communicating internal opening 210 facing the arrangement space 115, communicating external openings 220, 220B facing the fluid discharge hole, flow path forming surfaces 230, 230A connecting the communicating internal opening 210 and the communicating external openings 220, 220B, and at least one step portion 240 arranged between the communicating internal opening 210 and the communicating external opening 220, and the step portion 240 has a protruding surface 241 protruding vertically inward from the flow path forming surfaces 230, 230A, and a reverse inclined surface 242 inclined from the protruding surface 241 toward the communicating internal opening 210 so that the flow path cross-sectional area expands.

[0104] With this configuration, the protruding surface 241 and the inclined surface 242 form a flow path that gradually narrows and then suddenly widens when the fluid flows from the communicating internal opening 210 to the communicating external openings 220 and 220B. On the other hand, the protruding surface 241 and the inclined surface 242 form a flow path that rapidly narrows and then gradually widens when the fluid flows from the communicating external openings 220 and 220B to the communicating internal opening 210. Therefore, once liquid hydrogen begins to flow from the communicating internal opening 210 to the communicating external opening 220B, a continuous gradually narrowing flow path with low pressure loss is formed, and the wall shear force of the main flow is reduced due to cavity flow. As a result, flow path resistance to the flowing liquid hydrogen can be reduced. Therefore, liquid hydrogen can be quickly discharged from the arrangement space 115 to the fluid discharge hole through the first communication hole 105.

[0105] Furthermore, once the fluid begins to flow from the communicating outer opening 220 to the communicating inner opening 210, the circulating fluid flows through the protruding surface 241 and then the inverted inclined surface 242. Therefore, the fluid flows through a flow path that is abruptly narrowed by the protruding surface 241, and then flows through a flow path that is gradually widened by the inverted inclined surface 242. As a result, in the first communicating hole 105B, the resistance to the fluid flowing from the fluid discharge hole into the arrangement space 115 is greater than the resistance to the fluid flowing out from the arrangement space 115 to the fluid discharge hole. Therefore, the first communicating hole 105B allows for gradual discharge from the fluid discharge hole to the arrangement space 115. This makes it possible to control the flow rate difference between the outflow and inflow of liquid hydrogen through the first communicating hole 105B so that it is significantly asymmetric. This shortens the time until the opening state and lengthens the time until the closing state, thereby reducing the load.

[0106] (6) The discharge valve 42C according to the sixth aspect is any one of the discharge valves 42C according to (1) to (5), and further includes a closing member 153 that closes an external opening 152 formed in the casing that connects the storage space with the outside, and forms a sealed space 116 between the valve seat pressing member 103 and the closing member 153, and the valve seat pressing member 103 has a second communication hole 106 that connects the sealed space 116 with the arrangement space 115 at a position that does not overlap with the valve body 102 and the biasing member.

[0107] With this configuration, the fluid remaining in the arrangement space 115 can be continuously discharged to the sealed space 116 via the second communication hole 106 regardless of the movement of the valve body 102 and the biasing member.

[0108] (7) The boost pump 32 according to the seventh aspect comprises an intake valve 41 for drawing low-temperature fluid into a compression chamber 43, a piston 37 for compressing the low-temperature fluid drawn into the compression chamber 43 from the intake valve 41, and any one of discharge valves 42, 42A, 42B, 42C (1) to (6) for discharging the low-temperature fluid compressed by the piston 37.

[0109] With this configuration, when the discharge valves 42, 42A, 42B, 42C are in the open state and the closed state, the resistance to the fluid passing through the first communication holes 105, 105A, 105B can be made asymmetric, thereby shortening the time to reach the open state and lengthening the time to reach the closed state, thereby reducing the load.

[0110] (8) In an eighth aspect, the hydrogen supply system 10 includes a compressor 21 having a boost pump 32 of any one of (1) to (7) and compressing liquid hydrogen as a cryogenic fluid, an evaporator 22 that vaporizes the liquid hydrogen compressed by the compressor 21, and a dispenser 23 that supplies the hydrogen gas vaporized by the evaporator 22.

[0111] With this configuration, when the discharge valves 42, 42A, 42B, 42C are in the open state and the closed state, the resistance to the fluid passing through the first communication holes 105, 105A, 105B can be made asymmetric, thereby shortening the time to reach the open state and lengthening the time to reach the closed state, thereby reducing the load. [Explanation of symbols]

[0112] 10...Hydrogen supply system 11...Container 12...Vehicle 21...Compression device 22...Evaporation device 23...Dispenser 31...Drive motor 32...Booster pump 33…Reducer 34...Crank mechanism 35...Crosshead 36...Piston rod 37...Piston 38...Cylinder block 39…Container 41...suction valve 42, 42A, 42B, 42C...Discharge valve 43...Compression chamber 51...Mating hole 52...recess 52a…Small diameter hole 52b...Large diameter hole 53...Communication hole 53a…Main valve seat 61...Valve casing 61a...Main body 61b...Flange part 61c...Spring holder 62...First valve body 62a...Main rod section 62b...Head section 62c...Pressure surface 62d...Seat surface 63...Second valve body 63a...Opening 63b...Pressure surface 63c...Seat surface 64...Pressing member 71…Space part 72...Through hole 73...Suction hole 74…Discharge hole 75...Nut 76...Spring support member 77...Pump compression coil spring 81, 82...Sealing members 91... Fastening bolt 92...Suction pipe 101...Valve seat 101a...Valve seat receiving hole 102...Valve body 103... Valve seat holding member 103a...Cylindrical part 103b…Partition wall part 103c...Threaded section 103d...Pressing member accommodating hole 104...Compression coil spring 105,105A,105B…First series of holes 106…Second communication hole 111...ball 112...Support 112a...Receiving part 112b...Rod section 113...Inlet 114…Discharge port 115…Arrangement space part 116...Sealed space part 121, 122...Sealing member 151...Housing hole 151a...Block screw section 152...External opening 152a...Opening screw portion 153... Closing member 153a...Closing screw section 154...Fluid inflow hole 155...Annular flow path 210…Communication internal opening 220,220B…Communication external opening 230, 230A...flow path forming surface 231…Vertical plane 232…Slope surface 240...Double section 241...Protruding surface 242...Reverse slope VD: Vertical direction HD…horizontal direction

Claims

1. a casing having a fluid inlet hole and a fluid discharge hole, each of which communicates with the fluid discharge hole, and an accommodation space portion which communicates with the fluid discharge hole; a valve seat disposed in the accommodation space and having an inlet communicating with the fluid inlet hole and an outlet communicating with the fluid outlet hole; a valve body supported in the accommodation space portion so as to be movable between a closing position for closing the inlet and an opening position for opening the inlet; a valve seat pressing member that is disposed in the accommodation space and defines an arrangement space therein, the arrangement space being located on the opposite side of the inlet port with respect to the valve body in the accommodation space, and that determines the position of the valve seat relative to the casing; a biasing member disposed in the arrangement space and biasing the valve body to the closed position, the valve seat pressing member has a first communication hole that communicates the arrangement space with the fluid discharge hole, The first communication hole has a flow path shape that provides greater resistance to fluid flowing from the fluid discharge hole into the arrangement space than to fluid flowing out from the arrangement space to the fluid discharge hole.

2. the first communication hole has a communication inner opening facing the arrangement space, a communication outer opening facing the fluid discharge hole, and a flow path forming surface connecting the communication inner opening and the communication outer opening, The discharge valve according to claim 1 , wherein the cross-sectional area of the flow passage of the outer communicating opening is larger than the cross-sectional area of the flow passage of the inner communicating opening.

3. 3. The discharge valve according to claim 2, wherein the communicating external opening is located at a corner formed by the flow path forming surface and the outer peripheral surface of the valve seat pressing member, and is formed by a curved surface that gradually increases the cross-sectional area of the flow path.

4. 4. The discharge valve according to claim 2, wherein the flow passage forming surface has an inclined surface that gradually widens from the communication inner opening toward the communication outer opening.

5. the first communication hole has a communicating inner opening facing the arrangement space, a communicating outer opening facing the fluid discharge hole, a flow path forming surface connecting the communicating inner opening and the communicating outer opening, and at least one step portion disposed between the communicating inner opening and the communicating outer opening, 3. The discharge valve according to claim 1, wherein the step portion has a protruding surface that protrudes perpendicularly inward from the flow path forming surface, and a reverse inclined surface that is inclined from the protruding surface toward the communicating internal opening so that the flow path cross-sectional area increases.

6. a closing member formed in the casing to close an external opening that connects the accommodation space with the outside, and forming a sealed space between the closing member and the valve seat pressing member; 3. The discharge valve according to claim 1, wherein the valve seat pressing member has a second communication hole that communicates the sealing space with the arrangement space at a position that does not overlap with the valve body and the biasing member.

7. an intake valve for drawing the cryogenic fluid into the compression chamber; a piston that compresses the low-temperature fluid drawn into the compression chamber through the intake valve; a discharge valve according to claim 1 or 2, which discharges the cryogenic fluid compressed by the piston; A booster pump comprising:

8. a compression device having the boost pump according to claim 7 and compressing liquid hydrogen as a cryogenic fluid; an evaporator that vaporizes the liquid hydrogen compressed by the compressor; a dispenser for supplying the hydrogen gas vaporized by the vaporizer; A hydrogen supply system comprising:

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